* {
    margin: 0;
    padding: 0;
}

ul,
ol,
li {
    list-style: none;
}

img {
    vertical-align: top;
}

a {
    text-decoration: none;
}

.banner {
    width: 620px;
    height: 300px;
    margin: 100px auto;
}

.banner .pic {
    float: left;
    position: relative;
}

.banner .pic>ul>li {
    position: absolute;
    top: 0;
    left: 0;
}

.banner .pic>ul>li>a>img {
    width: 550px;
    height: 300px;
}

.banner .tab {
    float: right;
    width: 70px;
    height: 300px;
    background-color: #222;
}

.banner .tab>ul>li>a {
    display: block;
    height: 50px;
    text-align: center;
    line-height: 50px;
    color: #ccc;
    background-color: #222;
}

.banner .tab>ul>li.active>a {
    background-color: #C53A3A;
}

.banner .tab>ul>li {
    position: relative;
}

.banner .tab>ul>li.active>div.on {
    position: absolute;
    top: 20px;
    left: -12px;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 6px;
    border-color: transparent #C53A3A transparent transparent;
    z-index: 11;
}